The art is replete with such devices for applying lengths of pressure sensitive adhesive tape, U.S. Pat. Nos. 3,915,786 and 3,954,550 being illustrative examples. Such devices are commonly used to seal rectangular boxes filled with merchandise driven past the device by a conveyer. Typically, such devices include an application member such as a roller for supporting an end of tape adhesive side out in a contact position at which tape end will be contacted by a box. Upon such contact, tape end adheres to the box. Further movement of the box then pulls tape from the device between the box and the application member which presses tape against the contour of the box. Subsequently, the applied length of tape is severed from the supply length of tape and means on the device engages tape adjacent the newly severed end and moves it with the application member back to its contact position for contact by the next box on the conveyer.
Typically, the application member is mounted at one end of an arm which has its other end pivotably mounted at one edge of the path for the boxes so that after the leading surface of the box contacts the tape on the member, the member will revolve about the pivot point of the arm to follow the contour of the box and press tape sequentially against the leading surface of the box, around a leading edge of the box defined by adjacent edge portions of two butted cover flaps of the box, and then over adjacent portions of the cover flaps longitudinally of the box to seal the cover flaps together. Because of the increase in angle between the leading surface of the box and a line between the pivot point for the arm and the application member as the box moves along the path, however, the force applied by the leading surface of the box to move the application member across its leading surface will increase significantly as the application member approaches the edge of the box and can become sufficiently large just before the edge of the box passes the application member to push in the leading wall of the box under its two cover flaps, particularly for lightly constructed boxes. This can jam the tape applying apparatus or damage merchandise in the box, and even if it does not, it will produce a taped box in which tape bridges several centimeters between the cover flaps of the box and a portion of the front surface of the box, which bridging is unsightly and potentially insecure. Further, folding back of the corners of flaps on the box may occur.
U.S. Pat. No. 4,238,269, entitled "Tape Applying Device" and issued to Deering, Jr., the contents of which are incorporated herein by reference, discloses one approach to overcome this problem in conventional tape applying devices having pivotally mounted application members. The application member in the '269 patent is mounted for movement along a generally linear path from a contact position at which it will be contacted by the leading surface of a box to a second position at which it will be against the one side of the box as the box moves past the application member Preferably, the linear path is disposed at an angle in the range of about 35 to 55 degrees (preferably 45 degrees) with respect to the path for the box so that one component of movement of the application member from its contact position to its second position is in the direction of movement of the box. With this arrangement the force applied to the leading surface of the box to move the application member to its second position is essentially uniform as the application member traverses the leading surface of the box and can be adjusted via means biasing the application member to its contact position so that firm engagement of tape against the entire front surface of the box will be provided.
This approach improved on prior designs in that the uniform force applied against the box attenuated damage to boxes as tape was applied. However, although the force exerted against the box was reduced (i.e. the force was kept relatively uniform and did not increase) as the application member approaches the leading edge of the box, it has been discovered that the initial force of impact of the application member against the leading surface of the box sometimes reached undesirably high levels, depending on the size and strength of the box, the contents of the box, the velocity of the box, and the inertia of tape applying device, among other factors. Thus, under some circumstances, the tape applying device of the '269 patent would damage a box or its contents upon the initial impact between the box and the tape applying device, or the speed of boxes moving past the device had to be reduced.